Applications of Compounded Tetracaine in Oral Medicine

Tetracaine, previously referred to as amethocaine, is a potent local topical anesthetic of the ester class. Tetracaine acts by reversibly interrupting impulse conduction in peripheral nerves fibres and inhibiting depolarization by stabilizing excitable cell membranes by blocking sodium channels. ¹ It has been in use for a variety of purposes since the early 1930s, and its most common use is as a topical ophthalmic anesthetic for short procedures on the surface of the eye, as well as during surgical interventional procedures in the ears and/or nose. Now, compounded tetracaine preparations are often ordered for certain dental procedures and used during oral surgery as an anesthetic, for pharyngitis, oral mucositis, and more. ²ٰ ³ 

 

 

Administration

Tetracaine has a pKa of 8.46 at room temperature (25 degrees C), has a relatively quick onset of action, and is classified among the most potent of any local anesthetic. This molecule has a pH of 4.5 to 6.5 in plain solution and can be administered topically, subcutaneously, or via intrathecal injection. ² Because of its potency and high lipid solubility, tetracaine is also the most potent depressant of cardiac conduction and contractility. ⁶ Use of tetracaine in patients with cardiovascular issues should be closely monitored by a qualified health care practitioner.  

 

Recent advances have been reported for needle-free local anesthesia in oral medicine, particularly for maxillary teeth by administering a nasal spray of tetracaine and oxymetazoline without causing pain, fear, and stress. The results of said studies obtained were very encouraging. This nasal spray hybrid system could reduce cytotoxicity, promote sustained permeation, and increase the anesthetic efficacy for safe, effective, painless, and prolonged analgesia in dental procedures. ⁴

 

Tetracaine can be compounded as lollipops to serve as an alternative to oral anesthetics and this treatment caters to patients, especially in pediatrics, that have a strong aversion to oral care. This lollipop type delivery system has the ability to numb the oral mucosa without the prick of an injection, nor have the unpleasant taste of anesthesia in topical, lozenge, or spray forms. ⁵ 

 

Tetracaine has proven to be an effective, inexpensive, essential drug that can be used in various forms as a potent local anesthetic. Changing demographics and therefore medical management have altered the population’s oral care needs. As a result, new demands have been placed in the healthcare, namely for the dental and pharmaceutical industry, for increased knowledge and awareness in the diagnosis and medical management of oral mucosal diseases management of pain from procedures.

 

 Sample Formula

Tetracaine Hydrochloride 0.5% Lollipop⁵  As an analgesic, it can be used to relieve pain from sore throat, painful conditions of the oral cavity, and inhibit gag reflex during dental treatment.
Ingredients Sorbitol Candy Flavor (any if not using preflavored candy) Tetracaine Hydrochloride (Can be interchanged with Tetracaine Base) Propylene glycol	362g qs   2.05g (Tetracaine HCL), 2.32g (Tetracaine Base) 3mL qs
NOTES: 1. Each 1.13mg of tetracaine hydrochloride is equivalent to 1mg of tetracaine base. The tetracaine base works slower in the oral cavity but would last longer because of its high lipid solubility. 2. Each lollipop will weigh about 8g but the mold has to be calibrated. 3. This formula allows for 10% overage. 4. Excess can be saved as “taste chips” for the patient or physician to sample. METHOD OF PREPARATION 1. Calculate the required quantity of each ingredient for the total amount to be prepared 2. Accurately weight and/or measure each ingredient 3. Place the sorbitol candy in a 1000mL Erlenmeyer flask, and microwave on high for 4.5-5 minutes until it melts. 4. Wet the Tetracaine HCL with Propylene Glycol. 5. Remove the candy from the oven and stir the tetracaine into the melted candy mix with a mixer. Mix very well. 6. Prepare the mold by entirely coating it with a non-stick spray or an equivalent. Turn the mold upside down to allow the excess coating to drain. 7. Carefully pour the melt into the mold. Fill the mold completely and allow the excess melt to drain out of the holes. 8. Place the lollipop sticks into the holes containing the candy mix. Push the stick all the way into the mold cell, and then pull it out halfway. 9. Allow the mix to set in the mold for 24 hours. 10. Carefully open the mold, with a rubber mallet if necessary. 11. Carefully remove each lollipop from its cell and let sit on a paper towel to absorb excess non-stick coating.
STABILITY Beyond use is 180 days
PACKAGING AND LABELING Use as directed, keep out of reach of children, suck for 30-seconds to 1-minute and then replace in the container. The lollipop can be reused to anaesthetize an area in the oral cavity when the effects of the anesthetic diminish after eating or drinking.

 

 Disclaimer: Xenex Laboratories Inc. has provided the formula and instructions above as a model for educational purposes only on the basis of recognized compendia and texts or references. Xenex Laboratories Inc. takes no responsibility for the validity or accuracy of this information or for its safety or effectiveness, nor for any use thereof, which is at the sole risk of the licensed pharmacist. Adjustments may be needed to meet specific patient needs and in accordance with a licensed prescriber’s prescription. The pharmacist must employ appropriate tests to determine the stability of this suggested formula. Xenex Laboratories Inc., its owners, officers, agents, contractors, affiliates and employees cannot be held liable to any person or entity concerning claims, loss or damage caused by, or alleged to be caused by, directly or indirectly, the use or misuse of the information contained in this suggested formula. In all cases, it is the responsibility of the licensed pharmacist to know the law, to compound any finished product and to dispense these products in accordance with Health Canada and FDA guidelines and appropriate Provincial Drug Schedules and Provincial or Territorial Pharmacy Practice Standards. 

 

Reviewed by: Paul Gibbons B.Sc. Pharm. RPh.
May 6th, 2022

 

1. Haywood, A., Holt, M., & Glass, B. (2017). Solutions through compounding: Tetracaine lollipop for dental applications. Australian Pharmacist, 36(6), 44-47.
2. Stringer, C. M., Lopez, M. J., & Maani, C. V. (2020). Tetracaine. StatPearls [Internet].
3. Yuen, M. V., Gianturco, S. L., Pavlech, L. L., Storm, K. D., Yoon, S., & Mattingly, A. N. (2020). Benzocaine: Summary Report.
4. Calixto, G. M. F., Muniz, B. V., Castro, S. R., de Araujo, J. S. M., de Souza Amorim, K., Ribeiro, L. N., ... & Franz-Montan, M. (2021). Mucoadhesive, Thermoreversible Hydrogel, Containing Tetracaine-Loaded Nanostructured Lipid Carriers for Topical, Intranasal Needle-Free Anesthesia. Pharmaceutics, 13(11), 1760.
5. Case, T., & Deen, G. L. (2010). Tetracaine lollipops for the suppression of extreme gag reflex in dental patients. International Journal of Pharmaceutical Compounding, 14(5), 395.
6. Block A, Covino BGEffect of Local Anesthetic Agents on Cardiac Conduction and ContractilityRegional Anesthesia: The Journal of Neural Blockade in Obstetrics, Surgery, & Pain Control 1981;6:55-61.